1 | """ |
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2 | Encryption module that uses the Java Cryptography Extensions (JCE). |
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3 | |
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4 | Note that in default installations of the Java Runtime Environment, the |
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5 | maximum key length is limited to 128 bits due to US export |
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6 | restrictions. This makes the generated keys incompatible with the ones |
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7 | generated by pycryptopp, which has no such restrictions. To fix this, |
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8 | download the "Unlimited Strength Jurisdiction Policy Files" from Sun, |
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9 | which will allow encryption using 256 bit AES keys. |
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10 | """ |
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11 | from javax.crypto import Cipher |
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12 | from javax.crypto.spec import SecretKeySpec, IvParameterSpec |
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13 | |
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14 | import jarray |
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15 | |
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16 | # Initialization vector filled with zeros |
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17 | _iv = IvParameterSpec(jarray.zeros(16, 'b')) |
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18 | |
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19 | def aesEncrypt(data, key): |
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20 | cipher = Cipher.getInstance('AES/CTR/NoPadding') |
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21 | skeySpec = SecretKeySpec(key, 'AES') |
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22 | cipher.init(Cipher.ENCRYPT_MODE, skeySpec, _iv) |
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23 | return cipher.doFinal(data).tostring() |
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24 | |
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25 | |
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26 | def getKeyLength(): |
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27 | maxlen = Cipher.getMaxAllowedKeyLength('AES/CTR/NoPadding') |
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28 | return min(maxlen, 256) / 8 |
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